Know Your Supplements

Melissa HealyTribune Newspapers

The recent recall of a popular weight-loss supplement comes when Americans are more desperate than ever to lose weight -- and possibly more curious about what's in the supplements to which they turn for help.

In May, the Food and Drug Administration warned consumers to stop using Hydroxycut, a line of herbal dietary supplements marketed as an aid to weight loss, body sculpting and athletic performance. So far, the agency has not identified which of the many ingredients in Hydroxycut products, or its dosage, may have caused dangerous side effects. Since many of the ingredients in the formulations are found widely in other dietary supplements, the culprit -- if there is one -- may still be on the market. The following are among weight-loss ingredients most frequently used in these formulas.

Caffeine

Seldom acknowledged on the labels of dietary supplements promoted for weight loss, caffeine is almost uniformly their key ingredient. Its sources are many and extremely varied: green tea extract (or Camellia sinensis), guarana, yerba mate and kola nut, to name a few. In studies, high doses of caffeine have been shown to decrease appetite, but the effect doesn't last long.

Antioxidants

Glutathione, green tea extracts and, more recently, the Brazilian açai berry are among the many sources of antioxidants marketed in supplements as an aid to weight loss. In test tubes, antioxidants called flavenoids and phenolic acids have been found to cut the production of triglycerides in mouse fat cells. But their weight-loss properties in humans haven't been rigorously tested.

Bitter orange

After the FDA banned the sale of ephedra and other products containing ephedrine in 2004, marketers of dietary supplements for weight loss widely proclaimed extracts from the peel of bitter orange (Citrus aurantium) "the next ephedra."

Bitter orange (also called Seville orange and sour orange) is touted as an energy-enhancing fat burner, as was ephedrine. There is evidence that, like ephedrine, it may cause slightly more weight loss than diet and exercise alone. And the active ingredients in bitter orange extract -- synephrine and octopamine -- are related to ephedrine.

Hydroxycitric acid

The ingredient from which the Hydroxycut name was originally drawn is a derivative of the Malabar tamarind, or Garcinia cambogia. Used in traditional medicine to treat high cholesterol, it is touted as an agent that interferes with fat metabolism and possibly suppresses appetite.

Conjugated Linoleic Acid

Frequently included in products that promise to help dieters transform fat into lean muscle mass, CLA is a polyunsaturated fat found naturally in milk and meat, and is derived from the oil of sunflower (Helianthus annuus) and safflower (Carthamus tinctorius) seeds. One product that touts its power -- Phosphacore -- says that Carthamus tinctorius "may work to safely break up and flush away unhealthy adipose [fat] cells."

Cortisol blockers

Tinctures of golden root (Rhodiola rosea) or other herbs, such as rose root, are marketed as weight-loss aids on the argument that stress -- which causes the release of the hormone cortisol -- can lead to weight gain and, particularly, to the accumulation of belly fat. There is no evidence that blocking cortisol causes weight loss, or that herbal remedies lower cortisol levels.

Chitosan

The chemically cleansed product of grinding up the shells of shrimps, crabs and lobsters, chitosan is a powder that has been used in the water-purification industry for years: Sprinkled on top of holding tanks, it binds to lipids, or fats. Fats and oils can thus be skimmed off easily. This has led to the claim that supplements containing chitosan have "fat magnet" qualities, absorbing dietary fat before it can be absorbed into the gut and flushing it away.

But three human clinical trials found no difference in weight or serum cholesterol levels between subjects taking chitosan supplements and those taking a placebo. Chitosan could be dangerous to anyone with shellfish allergies.

Hoodia

A succulent plant native to the Kalahari Desert in Africa, hoodia (Hoodia gordonii) is chewed and eaten by San Bushmen to reduce their hunger and thirst during long hunts. In a 2004 study published in Brain Research, scientists injected p57, thought to be the active ingredient in hoodia, into a region of rats' brains thought to govern appetite. They found reduced activity there.